A kid gets flushed down a toilet and the movie doubles down on the refusal to explain anything. The comedy isn't in the jokes landing, it's in watching Takeshi, Jasmine, and Akuei operate in a world where an underwater UNCO fighting PIPS in Springtown, Taiwan is the baseline reality, and nothing needs justification. This is pure commitment to nonsense as the entire point.
Two Akuei films arrive together in a single comedy release: Counterattack of Chelsea and Akuei and His Magic Hammer. They continue the surreal gag franchise that began in fall 2004 with Akuei to Gacchinpo, where a boy named Takeshi gets sucked down a school toilet into an underwater world. There he joins the spunky Jasmine in the organization UNCO, which battles the evil PIPS, and the pair travel to Springtown, Taiwan, to team up with their friend and fellow member Akuei.